*{
    margin: 0;
    padding: 0;
}
.box{
    width: 100px;
    height: 100px;
    background-color: pink;
}
.box1{
    width: 300px;
    height: 300px;
    background-color: yellow;
    margin-bottom: 50px;
}
img{
    display: block;
}
li{
    list-style: none;
}
header{
    width: 100%;
    height: 50px;
    background-color: red;
    color: #ffffff;
    display: flex;
    justify-content:space-between;
    align-items:center ;
    box-sizing: border-box;
    padding:0 10px 0 10px;

}
nav{
    width: 100%;
    height: 60px;
    background-color: rgb(236, 234, 234);
}
ul{
    width: 100%;
    height: 100%;
    display: flex;
    justify-content:space-around;
    align-items: center;
}
nav ul li{
    width: 25%;
    height: 100%;
    text-align: center;
    line-height: 60px;
}
.bgRed{
    border-bottom: 2px solid red;
}